Sound-amplifying device



THAYER SOUND AMPLIFYTNG DEVICE Filed Nov. 1.7

1,701,515 PATENT OFFICE."

HENRY w. 'rrmvna, or onAyrnAM, new JnnsnY.

SOUND-AMPLIFYING nnvron.

Application filed November 17, 1927. Serial No. 233,793. I

This'invention relates, generally to'improvements in sound amplifying devices adapted to be magnetically or mechanically actuated to produce amplified sound waves;

and the invention has reference, more par-' ticularly, to a sound amplifying device of the loud speaker type for, use in connection with radio and telephonc communication.

This invention has for its principal object to provide anovel construction and arrangement of coupled vibratory diaphragms whereby transmitted sound is reproduced in amplified volume and with a high degree of resonance and clarity throughout the entire range of audio or musical frequencies, and especially whereby improved reproduction and amplified transmission of the lower ranges of audioor musical frequencies lS Ob". tained.

With the object of my present invent-ion in view, the same consists in providing a novel construction and arrangement of co axial diaphragms spaced apart to furnish an intermediate resonance chamber having sound wave outlets, said diaphragms being centrally coupled together for synchronous vibration under the transmitted impulses of a single magnetic or mechanical actuator, such as a tele hone receiving unit, a phonograph repro ucing unit, or other similar means for transmitting sound wave vibrations.

Other objects of the present invention, not

at this time more particularly enumerated,

will be clearly understood frbm the following detailed description of the same.

The invention is clearly illustrated in the accompanying drawings, in which:-

Fig. 1 is a face view of one form of coupled vibratory diaphragms for sound amplification made according to and embodyin the principles of this invention, the same eing shown in connection with an actuating telephone receiving unit, together with means for mounting the diaphragms in operative relation to the latter; and Fig. 2 is a vertical section, taken on line 2--2 in Fig. 1.

Fig. 3 is a face view in part transverse vertical section of a modified form of coupled vibratory diaphragms forsound amplification which embodies, however, the general principles of construction and arrangement according to this invention; Fig. 4 is a vertical section through the same, takenon line H in Fig. 3. n

tory results,

Similar characters ofv reference are employed in the above, described views, to indicate corresponding parts.

Referring first to Fi s. 1 and 2 of the drawings, 1 have shown t erein the preferred form of amplifying device according to this invention, the same comprising a rear diaphragm 5 and a front diaphragm 6 axially aligned together in spaced relation, and respectively mounted on opposite sides of a peripheral frame so as to provide an intermediate resonance chamber 7. In said preferred form, the front diaphragm 6 is of less diameter than the rear diaphragm 5. The peripheral frame for supporting the diaphragms and bounding the resonance chamber? comprises an annular frame member 8 disposed to occupy-a plane parallel to the planes of the dlap ragms';- said frame memer 8 having at its outer periphery a rearwardly projecting annular shoulder 9 and at its inner eriphery a forwardly. projecting annular s on der 10. The-marginal portions of the rear diaphragm 5 are registered against and secured to said shoulder 9 and the marginal portions of the front diaphragm are registered against and secured to said shoulder'lO, all in such manner ,thatthe frame member 8 serves to support the diaphragms for vibration and yet properly spaced apart to provide the desired intermediate resonance chamber 7.- Said frameflmember 8 is rovided,iin spaced apart relation aroun its circumference, with a plurality .of sound wave outlets or o enings 11 leading from the -interior of sai resonance chamber 7. The diaphragms 5 and 6 may be secured to the frame member 8 by any suitable or convenient means, as, for example, by an adhesive hinder, or, if desired, by an form of mechanical fastening. Said ditipiiragms 5 and 6 may be made of any suitable material which is sufficiently flexible to permit of the required vibratory action thereof; in this connection, I have found parchment, paper, fiber board and similar materials to give very satisfacand to be entirely free from me tallic timbre. The diaphragms 5 and 6 are centrally connected together by a substantially rigid intermediate coupling post 12 so that the same vibrate synchronously under the transmitted impulses of a sin 1e actuating means, such as a phonograp iic reproducer, or a magnetic telephone receiver, etc., which operate to transmit vibrations corresponding to sound wave vibrations at the frequencies of music and speech.

The present invention is especially adapted to amplify vibrations to reproduce sound in connection with radio communication, and I have therefore illustrated the invention in the form adapting the'same to serve as a socalled loud speaker. To such end I provide a suitable supporting standard extending upwardly from a base 13, said standard preferably taking the form of a pair of laterally spaced uprights 14 and 15 having an intermediate transverse shelf or support 16 upon which the telephonic receiving unit is mounted in axial alignment with and behind the diaphragms. Said diaphragms are secured to said uprights 14 and 15 by fastening devices, such as the screws 17, which pass through the, frame member 8 into said uprights, the latter preferably having outwardly projecting abutments 18 at the points of connection so., that the rear diaphragm 5 is spaced reely from the uprights to avoid any interference with the operative vibration of said diaphragms. Mounted on the shelfor support 16 is a telephonic receiving unit 19 of any well-known type having a transmissionrod 20 through which the magnetically induced vibrations of said unit may be transmitted to the amplifying diaphragms. To operatively connect the diaphragms with the transmission rod 20, therear diaphragm 5 is provided at its exterior face with a centrally located coupling element 21 having a socket portion 22 to receive the free end of said transmission rod 20, which is detachably secured by a set screw 23 or other suitable locking means. ment is provided with a screw threaded shank' 24 which screws into an internally threaded sleeve 25 imbedded in the adjacent end ofsaid coupling post 12, all whereby the vibratory movements of said unit 19 are synchronously, transmitted to the diaphragms 5 and '6. v v

I have found the amplifying device of this invention to be very effective in clearly reproducing, in large volume, sounds such as music and speech without distortion, metallic uality, or necessity for the use of dispersion devices such as horns, etc; and, furthermore, the device is especially efiective in reproducing musical notes, drum beats and the like, in

the lower ranges of audio or musical frequencies. In operation, the coupled diaphragms being actuated synchronously, the

vibration of the front diaphragm 6 directly excites the-freeair in contact therewith at its exterior surface to regenerate the sound waves to be communicated, while at the same time, operating in conjunction therewith, the correspondingly vibrating rear diaphragm excites the air within the resonance chamber 7 so that sound waves especially of relatively low frequency range are more efliciently re- Preferably said coupling ele-.

produced and propagated and then dispersed through the outlets or openings 11. of the bounding frame member 8.

In practice, I prefer to employ the form of my invention shown in Figs. 1 and 2, in which th front diaphragm 6 is of less diameter than the rear diaphragm 5, since the comparatively greater surface areaof the latter aids in increasing the amplitude of corresponding sound wave producing air pulsations within the resonance chamber 7 to there by augment the propagation and dispersion of sound waves of relatively low frequency range.

While I prefer to employ the form of my invention shown in Figs. 1 and 2 as aforesaid, I do not wish to be understood as necessarily confining the scope of my invention to such form, for, in its broader aspects, involving a plurality of coupled synchronously vibrated diaphragms with intermediate resonance chamber, it is within its spirit to employ diaphragms of the same size. This latter arrangement I have illustrated in Figs. 3 and 4 of the accompanying drawings, wherein the reference character 26 indicates a rear diaphragm and 27 a front diaphragm of substantially equal size. Said diaphragms 26 and 27 are supported in parallel spaced apart relation, so as to provide the desired intermediate resonance chamber 28, by an annular frame member 29 which is interposed and secured between their marginal portions. Said frame member is provided with radial openings 30 spaced around the circumference thereof to provide outlets for the dispersion of sound waves produced by pulsations of air within said resonance chamber. The diaphragms 26 and 27 are centrally connected together for synchronous vibration by the intermediate coupling post 12, in connection with which and said rear diaphragm is provided the coupling element 21 and associated parts already above described, and by means of which the device may be operatively connected with and so as to be actuated by a telephone receiving unit.

I am aware that some changes, other than those already above indicatethmay be made in the general construction and arrangement of the sound amplifying device as above described and as illustrated in the accompanying drawings, as well as in the details of the construction of the same without departing from the spirit and scope of the invention as defined by the appended claims. It is therefore to be understood that the specific disclosures of the specification and drawings are to be considered as illustrative and not in a limiting sense.

Having described my invention, I claim:

1. A sound amplifying device, comprising a plurality of spaced diaphragms centrally coupled for synchronous vibration, a peripheral frame means to which the marginal portions of said diaphragms secured to" provide resonance space intermediate the lat-' ter, said frame having dispersion openings leading therethrough from said resonance space, and means to transmit-vibratory motion to said diaphragms.

2. A sound amplifying device, comprising a pair of axially aligned diaphragms, an an- -nular frame member intermediate the margins of said diaphragms to which the latter are secured whereby a resonance chamber intermediate said diaphragms and bounded by said frame member is provided, said frame member having dispersion openings leading therethrough from said resonance/chamber,

' means to interconnect said diaphragms for synchronous vibration, and means to transmit vibratory motion to said diaphragms.

3. A sound amplifying device, comprising a pair of spaced diaphragms, means con nected with the marginal portions of said diaphragms to support the same and to form a resonance chamber therebetween, said latter means having dispersion openings leading therethrough from said resonance chamber, a centrally disposed substantially rigid coupling post interconnecting raid dia- .phragms for synchronous vibration, a telephonic receiving unit, a transmission rod actuated by said unit; external means centrally connected with one of said diaphragms for operatively connecting said transmission therewith, and means to support said dia-. phragms and unit in assembled cooperative relation.

i. A sound amplifying device, comprising a rear diaphragm, a front diaphragm of reduced diameter, an annular frame interconnecting the margins of said diaphragms to hold the same in spaced relation to provide an intermediate resonance chamber, said frame having dispersion openings leading therethrough from said resonance chamber,-

a-centrally disposed substantially rigid coupling post interconnecting said diapliragrns for synchronous vibration, and" means to transmit vibratory motion to said diaphragms,

5. A sound amplifying device, comprising a rear diaphragm, a front diaphragm of reduced diameter, an annular frame interconnecting the margins of said diaphragms to hold the same in spaced relation to provide an intermediate resonance chamber, said frame having dispersion openings leadi g therethrough from said resonance chamber, a centrally disposed substantially rigid coupling post interconnecting said dia hragms for HENRY W. THAYER. 

